1. Field of the Invention
The present invention relates to continuous stationery for use in computer-controlled printing apparatus and particularly relates to continuous stationery for use in a point-of-sale terminal wherein a permanent record of a transaction is made for retention by the user and a copy, by way of a receipt, is provided for the customer.
2. The Prior Art
It is known to use continuous stationery in a point-of-sale terminal. Prior art stationery consists in a back ply and a front ply held together by paper staples. Sprocket holes are through-penetrative of both front and back plies and are used for aligning the continuous stationery in the point-of-sale terminal. The point-of-sale terminal includes a printer for writing on the continuous stationery. The continuous stationery is drawn from a first fanfold pile, printed upon by the point-of-sale terminal, the top ply detached and handed to the customer by way of a receipt, and the back ply refolded and kept as a continuous record.
Because of the compactness of construction of a point-of-sale terminal and the requirement for the provision of data communication and data processing elements therein, the construction of the printing apparatus in a point-of-sale terminal differs in some material aspects from the construction to be found in a normal computer-driven printer. Firstly, in order to minimize the volume of the point-of-sale terminal, the pin roller assembly for aligning the continuous stationery via the sprocket holes is provided remotely from the print head and before the print anvil whereas in a normal computer printer the pin roller assembly is provided proximate to the print head and anvil. Secondly, it is the custom in point-of-sale terminals to drive the continuous stationery by means of friction roller bearings. The continuous stationery is gripped between two rollers, at least one of which is driven, and fed through the point-of-sale terminal.
Several problems exist in using conventional, continuous stationery in a point-of-sale terminal. Because of the required exit orientation of the printed stationery from the point-of-sale terminal and the remoteness of the pin roller assembly from the printing head, the continuous stationery passes over the pin roller assembly in what, in other equipment, would be an upside down manner. The front ply being affixed to the back ply by paper staples, and the pin roller assembly being provided with sprocket covers, the protruding parts of the paper staples can jam in the sprocket cover and bring the whole apparatus to a halt, requiring the rethreading of the continuous stationery.
The pair of friction rollers driving the continuous stationery through the point-of-sale terminal, because of the weakness of paper staples, can cause the front ply to shear from the back ply thereby causing a risk of jamming a misregistration in the printer.
The form, having been printed, requires to have the front ply removed from the back ply in order that the customer may receive his receipt. Once again, because of the weakness of paper staples, there is a good chance that the paper staples will give way before the perforate line in the front ply running along the length of the continuous stationery. This results in the customer being handed a receipt complete with edge portions and sprocket holes. This is not aesthetically pleasing. Alternatively, the point-of-sale operator may be required to strip the edge portions with the sprocket holes from the customers receipt. In either case the uncertainty of the detachment of the receipt in the front ply is an undesirable feature.
Further, the perforate lines between adjacent forms in the front ply of the continuous stationery create a risk that in tearing off a receipt for a customer the user of the point-of-sale terminal may begin to tear off the portion of the front ply which would be the receipt for a customer on a following form.
It is therefore desirable to provide continuous stationery for use in a point-of-sale terminal having a pin roller assembly whereover the stationery passes in an inverted manner, wherein the stationery is driven by friction rollers, wherein the receipt portion of the front ply is assured of removal free of edge portions and sprocket holes, and wherein the portion of the front ply in one transaction form which is detached by way of receipt is assured of detachment without commencing the detachment of the corresponding portion in a following transaction form.